Cleaning Apparatus Using Solid Particulate Cleaning Material

ABSTRACT

There is disclosed an apparatus and method for use in the cleaning of soiled substrates, the apparatus including housing means having a first upper chamber having mounted therein a rotatably mounted cylindrical cage and a second lower chamber located beneath the cylindrical cage; at least one recirculation means; access means; pumping means and a multiplicity of delivery means, wherein the rotatably mounted cylindrical cage includes a drum including perforated side walls wherein up to 60% of the surface area of the side walls includes perforations and the perforations include holes having a diameter of no greater than 25.0 mm. The method carried out by the apparatus involves cleaning a soiled substrate by treatment of the moistened substrate with a formulation including solid particulate cleaning material and wash water.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 13/577,528 filed Aug. 7, 2012, which is a 35 U.S.C.§371 U.S. national phase entry of International Application No.PCT/GB2011/050243 having an international filing date of Feb. 10, 2011,which claims the benefit of Great Britain Application No. 1002245.7filed Feb. 10, 2010, each of which is incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

The present invention relates to the aqueous cleaning of substratesusing a cleaning system which requires the use of only limitedquantities of energy, water and detergent. Most particularly, theinvention is concerned with the cleaning of textile fibres and fabricsby means of such a system, and provides an apparatus adapted for use inthis context.

BACKGROUND TO THE INVENTION

Aqueous cleaning processes are a mainstay of both domestic andindustrial textile fabric washing. On the assumption that the desiredlevel of cleaning is achieved, the efficacy of such processes is usuallycharacterised by their levels of consumption of energy, water anddetergent. In general, the lower the requirements with regard to thesethree components, the more efficient the washing process is deemed. Thedownstream effect of reduced water and detergent consumption is alsosignificant, as this minimises the need for disposal of aqueouseffluent, which is both extremely costly and detrimental to theenvironment.

Such washing processes involve aqueous submersion of fabrics followed bysoil removal, aqueous soil suspension, and water rinsing. In general,within practical limits, the higher the level of energy (ortemperature), water and detergent which is used, the better thecleaning. The key issue, however, concerns water consumption, as thissets the energy requirements (in order to heat the wash water), and thedetergent dosage (to achieve the desired detergent concentration). Inaddition, the water usage level defines the mechanical action of theprocess on the fabric, which is another important performance parameter;this is the agitation of the cloth surface during washing, which plays akey role in releasing embedded soil. In aqueous processes, suchmechanical action is provided by the water usage level in combinationwith the drum design for any particular washing machine. In generalterms, it is found that the higher the water level in the drum, thebetter the mechanical action. Hence, there is a dichotomy created by thedesire to improve overall process efficiency (i.e. reduce energy, waterand detergent consumption), and the need for efficient mechanical actionin the wash. For domestic washing in particular there are defined washperformance standards specifically designed to discourage the use ofsuch higher levels in practice, in addition to the obvious costpenalties which are associated with such usage.

Current efficient domestic washing machines have made significantstrides towards minimising their consumptions of energy, water anddetergent. EU Directive 92/75/CEE sets a standard which defines washingmachine energy consumption in kWh/cycle (cotton setting at 60° C.), suchthat an efficient domestic washing machine will typically consume <0.19kWh/kg of washload in order to obtain an ‘A’ rating. If waterconsumption is also considered, then ‘A’ rated machines use <9.7litres/kg of washload, whilst the most efficient modern machines are nowcapable of using even less water—e.g. model number F1480FD6 manufacturedby LG (see www.Ig.com). This machine typically uses 63 litres for a 9 kgwashload, i.e. 7 litres/kg.

Detergent dosage is then driven by manufacturer recommendations but,again, in the domestic market, for a concentrated liquid formulation, afigure of 35 ml (or 37 g) for a 4-6 kg washload in soft and mediumhardness water, increasing to 52 ml (or 55 g) for a 6-8 kg washload (orin hard water or for very dirty items) is typical (see, for example,Unilever pack dosage instructions for Persil® Small & Mighty). Hence,for a 4-6 kg washload in soft/medium water hardness, this equates to adetergent dosage of 7.4-9.2 g/kg whilst, for a 6-8 kg washload (or inhard water or for very dirty items), the range is 6.9-9.2 g/kg.

Energy, water and detergent consumptions in the industrial washingprocess (washer-extractors) are considerably different, however, andusages of energy and water are less constrained in such environments,since these are principal factors in reducing cycle time—which is, ofcourse, more of a consideration than in the domestic scenario. There isa similar pressure on detergent levels, however, but this is mostly dueto a desire to reduce cost.

Thus, it can be taken from the above discussion that the performancelevels which set the highest standard for an efficient fabric washingprocess are an energy consumption of <0.19 kWh/kg, a water usage ofapproximately 7 litres/kg, and a detergent dosage of approximately 8g/kg. However, as already mentioned, it is becoming increasinglydifficult to reduce the water (and, hence, energy and detergent) levelsin a purely aqueous process, due to the minimum requirement to wet thefabric thoroughly, the need to provide sufficient excess water tosuspend the soil removed in an aqueous liquor and, finally, the need torinse the fabric.

Heating of the wash water is then the principal use of energy, and aminimum level of detergent becomes necessary in order for an effectiveconcentration to be reached at the operating wash temperature. If ameans to improve mechanical action could be achieved without increasingthe water level used, then the aqueous wash process could becomesignificantly more efficient (i.e. yield further reductions in energy,water and detergent consumption). It should be noted that mechanicalaction itself has a direct effect on the detergent level, since thegreater the level of soil removal which is achieved through physicalforce, the less that is required of the detergent chemistry. However,increasing the mechanical action in a purely aqueous washing process hascertain associated drawbacks. Fabric creasing readily occurs in suchprocesses, and this acts to concentrate the stresses from mechanicalaction at each crease, resulting in localised fabric damage. Preventionof such fabric damage (i.e. fabric care) is of primary concern to thedomestic consumer and the industrial user.

Various different approaches to the development of new cleaningtechnologies have been reported in the prior art, including methodswhich rely on electrolytic cleaning or plasma cleaning, in addition toapproaches which are based on ozone technology, ultrasonic technology orsteam technology. Thus, for example, WO-A-2009/021919 teaches a fabriccleaning and disinfection process which utilises UV-produced ozone alongwith plasma. An alternative technology involves cold water washing inthe presence of specified enzymes, whilst a further approach which isparticularly favoured relies on air-wash technology and, for example, isdisclosed in US-A-2009/0090138. In addition, various carbon dioxidecleaning technologies have been developed, such as the methods usingester additives and dense phase gas treatments which are described inU.S. Pat. No. 7,481,893 and US-A-2008/0223406, although such methodsgenerally find greater applicability in the field of dry cleaning. Manyof these technologies are, however, technically complex and not readilysuited to domestic applications, in particular.

In the light of the challenges which are associated with aqueous washingprocesses, the present inventors have previously devised a new approachto the problem, which is technologically straightforward, and yet stillallows the deficiencies demonstrated by the methods of the prior art tobe overcome. The method which is provided eliminates the requirement forthe use of large volumes of water, but is still capable of providing anefficient means of cleaning and stain removal, whilst also yieldingeconomic and environmental benefits.

Thus, in WO-A-2007/128962 there is disclosed a method and formulationfor cleaning a soiled substrate, the method comprising the treatment ofthe moistened substrate with a formulation comprising a multiplicity ofpolymeric particles, wherein the formulation is free of organicsolvents. Preferably, the substrate is wetted so as to achieve asubstrate to water ratio of between 1:0.1 to 1:5 w/w, and optionally,the formulation additionally comprises at least one cleaning material,which typically comprises a surfactant, which most preferably hasdetergent properties. In preferred embodiments, the substrate comprisesa textile fibre and the polymeric particles may, for example, compriseparticles of polyamides, polyesters, polyalkenes, polyurethanes or theircopolymers, but are most preferably in the form of nylon chips.

The use of this cleaning method, however, presents a requirement for thecleaning chips or beads to be efficiently separated from the cleanedsubstrate at the conclusion of the cleaning operation, and this issuewas initially addressed in WO-A-2010/094959, which provides a noveldesign of cleaning apparatus requiring the use of two internal drumscapable of independent rotation, and which finds application in bothindustrial and domestic cleaning processes.

With a view to providing a simpler, more economical means for addressingthe problem of efficient separation of the cleaning media from thesubstrate at the conclusion of the cleaning process, however, a furtherapparatus is disclosed in co-pending PCT Patent Application No.PCT/GB2010/051960. The apparatus of PCT Patent Application No.PCT/GB2010/051960, which finds application in both industrial anddomestic cleaning processes, comprises a perforated drum and a removableouter drum skin which is adapted to prevent the ingress or egress offluids and solid particulate matter from the interior of the drum. Thecleaning method requires attachment of the outer skin to the drum duringa first wash cycle, after which the skin is removed prior to operating asecond wash cycle, following which the cleaned substrate is removed fromthe drum.

The apparatus and method of PCT Patent Application No. PCT/GB2010/051960is found to be extremely effective in successfully cleaning substrates,but the requirement for the attachment and removal of the outer skindetracts from the overall efficiency of the process and the presentinventors have, therefore, sought to address this aspect of the cleaningoperation and to provide a process wherein this procedural step is nolonger necessary. Thus, by providing for continuous circulation of thecleaning chips during the cleaning process, it has been found possibleto dispense with the requirement for the provision of an outer skin.

SUMMARY OF THE INVENTION

Thus, according to a first aspect of the present invention, there isprovided an apparatus for use in the cleaning of soiled substrates, saidapparatus comprising:

-   -   (a) housing means, having:        -   (i) a first upper chamber having mounted therein a rotatably            mounted cylindrical cage, and        -   (ii) a second lower chamber located beneath said cylindrical            cage;    -   (b) at least one recirculation means;    -   (c) access means;    -   (d) pumping means; and    -   (e) a multiplicity of delivery means,        wherein said rotatably mounted cylindrical cage comprises a drum        comprising perforated side walls, wherein up to 60% of the        surface area of said side walls comprises perforations, and said        perforations comprise holes having a diameter of no greater than        25.0 mm.

In preferred embodiments of the invention, no more than 50%, morepreferably no more than 40%, of the side walls comprises perforations.

Preferably, said perforations comprise holes having a diameter of from 2to 25 mm, preferably from 4 to 10 mm, most preferably from 5 to 8 mm.

Said access means typically comprises a hinged door mounted in thecasing, which may be opened to allow access to the inside of thecylindrical cage, and which may be closed in order to provide asubstantially sealed system. Preferably, the door includes a window.Optionally, said door also includes at least one addition port whichfacilitates the addition of materials to said rotatably mountedcylindrical cage.

Said rotatably mounted cylindrical cage may be mounted vertically withinsaid housing means but, most preferably, is mounted horizontally withinsaid housing means. Consequently, in preferred embodiments of theinvention, said access means is located in the front of the apparatus,providing a front-loading facility. When the rotatably mountedcylindrical cage is vertically mounted within the housing means, theaccess means is located in the top of the apparatus, providing atop-loading facility. However, for the purposes of the furtherdescription of the present invention, it will be assumed that saidrotatably mounted cylindrical cage is mounted horizontally within saidhousing means.

Rotation of said rotatably mounted cylindrical cage is effected by useof drive means, which typically comprises electrical drive means, in theform of an electric motor. Operation of said drive means is effected bycontrol means which may be programmed by an operative.

Said rotatably mounted cylindrical cage is of the size which is to befound in most commercially available washing machines and tumble driers,and may have a capacity in the region of 10 to 7000 litres. A typicalcapacity for a domestic washing machine would be in the region of 30 to120 litres whilst, for an industrial washer-extractor, capacitiesanywhere in the range of from 120 to 7000 litres are possible. A typicalsize in this range is that which is suitable for a 50 kg washload,wherein the drum has a volume of 450 to 650 litres and, in such cases,said cage would generally comprise a cylinder with a diameter in theregion of 75 to 120 cm, preferably from 90 to 110 cm, and a length ofbetween 40 and 100 cm, preferably between 60 and 90 cm. Generally, thecage will have 10 litres of volume per kg of washload to be cleaned.

Said apparatus is designed to operate in conjunction with soiledsubstrates and cleaning media comprising a solid particulate material,which is most preferably in the form of a multiplicity of polymericparticles. These polymeric particles are required to be efficientlycirculated to promote effective cleaning and the apparatus, therefore,preferably includes circulation means. Thus, the inner surface of thecylindrical side walls of said rotatably mounted cylindrical cagepreferably comprises a multiplicity of spaced apart elongatedprotrusions affixed essentially perpendicularly to said inner surface.Preferably, said protrusions additionally comprise air amplifiers whichare typically driven pneumatically and are adapted so as to promotecirculation of a current of air within said cage. Typically saidapparatus comprises from 3 to 10, most preferably 4, of saidprotrusions, which are commonly referred to as lifters.

In operation, agitation is provided by rotation of said rotatablymounted cylindrical cage. However, in preferred embodiments of theinvention, there is also provided additional agitating means, in orderto facilitate the efficient removal of residual solid particulatematerial at the conclusion of the cleaning operation. Preferably, saidagitating means comprises an air jet.

Said rotatably mounted cylindrical cage is located within a first upperchamber of said housing means and beneath said first upper chamber islocated a second lower chamber which functions as a collection chamberfor said cleaning media. Preferably, said lower chamber comprises anenlarged sump.

Said housing means is connected to standard plumbing features, therebyproviding at least one recirculation means, in addition to amultiplicity of delivery means, by virtue of which at least water and,optionally, cleaning agents such as surfactants may be introduced intothe apparatus. Said apparatus may additionally comprise means forcirculating air within said housing means, and for adjusting thetemperature and humidity therein. Said means may typically include, forexample, a recirculating fan, an air heater, a water atomiser and/or asteam generator. Additionally, sensing means may also be provided fordetermining, inter alia, the temperature and humidity levels within theapparatus, and for communicating this information to the control means.

Thus, said apparatus comprises at least one recirculation means, therebyfacilitating recirculation of said solid particulate material from saidlower chamber to said rotatably mounted cylindrical cage, for re-use incleaning operations. Preferably, said first recirculation meanscomprises ducting connecting said second chamber and said rotatablymounted cylindrical cage. More preferably, said ducting comprisesseparating means for separating said solid particulate material fromwater and control means, adapted to control entry of said solidparticulate material into said cylindrical cage. Typically, saidseparating means comprises a filter material such as wire mesh locatedin a receptor vessel above said cylindrical cage, and said control meanscomprises a valve located in feeder means, preferably in the form of afeed tube attached to said receptor vessel, and connected to theinterior of the cylindrical cage.

Recirculation of solid particulate matter from said lower chamber tosaid rotatably mounted cylindrical cage is achieved by the use ofpumping means comprised in said first recirculation means, wherein saidpumping means are adapted to deliver said solid particulate matter tosaid separating means and said control means, adapted to control there-entry of said solid particulate matter into said rotatably mountedcylindrical cage. Preferably, said apparatus additionally includes asecond recirculation means, allowing for the return of water separatedby said separating means to said lower chamber, thereby facilitatingre-use of said water in an environmentally beneficial manner.

Preferably, said lower chamber comprises additional pumping means topromote circulation and mixing of the contents thereof, in addition toheating means, allowing the contents to be raised to a preferredtemperature of operation.

In operation, during a typical cycle, soiled garments are first placedinto said rotatably mounted cylindrical cage. Then, the solidparticulate material and the necessary amount of water, together withany required additional cleaning agent, are added to said rotatablymounted cylindrical cage. Optionally, said materials are heated to thedesired temperature in the lower chamber comprised in the housing meansand introduced, via the first recirculation means, into the cylindricalcage. Alternatively, said cleaning agent may, for example, be pre-mixedwith water and added either via an addition port mounted on the accessmeans or through said separating means located above said cylindricalcage. Optionally, this water may be heated. Additional cleaning agents,of which bleach is a typical example, may be added with more, optionallyheated, water at later stages during the wash cycle, using the samemeans.

During the course of agitation by rotation of the cage, the fluids and aquantity of the solid particulate material fall through the perforationsin the cage and into the lower chamber of the apparatus. Thereafter, thesolid particulate material may be re circulated via the firstrecirculation means such that it is transferred to said separatingmeans, from which it is returned, in a manner controlled by said controlmeans, to the cylindrical cage for continuation of the washingoperation. This process of continuous circulation of the solidparticulate material continuous throughout the washing operation untilcleaning is completed.

Thus, the solid particulate material which falls through theperforations in the walls of said rotatably mounted cylindrical cage andinto said lower chamber is carried to the top side of said rotatablymounted cylindrical cage, wherein it is caused, by means of gravity, tofall through said separation means and, by operation of control means,through said feeder means and back into said cage, thereby to continuethe cleaning operation.

According to a second aspect of the present invention, there is provideda method for cleaning a soiled substrate, said method comprising thetreatment of the substrate with a formulation comprising solidparticulate cleaning material and wash water, wherein said method iscarried out in an apparatus according to the first aspect of theinvention.

Preferably, said method comprises the steps of:

-   -   (a) introducing a solid particulate cleaning material and water        into the second lower chamber of an apparatus according to the        first aspect of the invention;    -   (b) agitating and heating said solid particulate cleaning        material and water;    -   (c) loading at least one soiled substrate into said rotatably        mounted cylindrical cage via access means;    -   (d) closing the access means so as to provide a substantially        sealed system;    -   (e) introducing said solid particulate cleaning material and        water into said rotatably mounted cylindrical cage via        recirculating means;    -   (f) operating the apparatus for a wash cycle, wherein said        rotatably mounted cylindrical is caused to rotate and wherein        fluids and solid particulate cleaning material are caused to        fall through perforations in said rotatably mounted cylindrical        cage into said second lower chamber in a controlled manner;    -   (g) operating pumping means so as to transfer fresh solid        particulate cleaning material and recycle used solid particulate        cleaning material to separating means;    -   (h) operating control means so as to add said fresh and recycled        solid particulate cleaning material to said rotatably mounted        cylindrical cage in a controlled manner; and    -   (i) continuing with steps (f), (g) and (h) as required to effect        cleaning of the soiled substrate.

Preferably, additional cleaning agents are employed in said method. Saidadditional cleaning agents may be added to the lower chamber of saidapparatus with said solid particulate cleaning material, optionallyheated to the desired temperature therein and introduced, via the firstrecirculation means, into the cylindrical cage. Preferably, however,said additional cleaning agents are pre-mixed with water, which mixturemay optionally be heated before addition to said cylindrical cage via anaddition port mounted on the access door. Optionally, this addition maybe carried out using a spray head in order to better distribute saidcleaning agents in the washload. Alternatively, said addition ofcleaning agents may be made via the separating means located above saidcage.

Preferably, pumping of said fresh and recycled solid particulatecleaning material proceeds at a rate sufficient to maintainapproximately the same level of cleaning material in said rotatablymounted cylindrical cage throughout the cleaning operation, and toensure that the ratio of cleaning material to soiled substrate stayssubstantially constant until the wash cycle has been completed.

The generation of suitable G forces, in combination with the action ofthe solid particulate cleaning material, is a key factor in achieving anappropriate level of cleaning of the soiled substrate. G is a functionof the cage size and the speed of rotation of the cage and,specifically, is the ratio of the centripetal force generated at theinner surface of the cage to the static weight of the washload. Thus,for a cage of inner radius r (m), rotating at R (rpm), with a washloadof mass M (kg), and an instantaneous tangential velocity of the cage v(m/s), and taking g as the acceleration due to gravity at 9.81 m/s²:

Centripetal force=Mv ² /r

Washload static weight=Mg

v=2πrR/60

Hence, G=4π² r ² R ²/3600rg=4π² rR ²/3600g=1.118×10⁻³ rR ²

When, as is usually the case, r is expressed in centimetres, rather thanmetres, then:

G=1.118×10⁻⁵ rR ²

Hence, for a drum of radius 49 cm rotating at 800 rpm, G=350.6.

In a preferred embodiment of the invention, a cylindrical drum having adiameter of 98 cm is rotated at a speed of 30-800 rpm in order togenerate G forces of 0.49-350.6 at different stages during the cleaningprocess. In examples of alternative embodiments of the invention, a 48cm diameter drum rotating at 1600 rpm can generate 687 G, whilst a 60 cmdiameter drum at the same speed of rotation generates 859 G.

In preferred embodiments of the invention, the claimed methodadditionally provides for separation and recovery of the solidparticulate cleaning material, and this may then be re-used insubsequent washes.

During the wash cycle, rotation of said rotatably mounted cylindricalcage is preferably caused to occur at rotation speeds such that G is <1which, for a 98 cm diameter cage, requires a rotation speed of up to 42rpm, with preferred rates of rotation being between 30 and 40 rpm.

On completion of the wash cycle, feeding of solid particulate cleaningmaterial into the rotatably mounted cylindrical cage ceases and thespeed of rotation of the cage is initially increased in order to effecta measure of drying of the cleaned substrate, thereby generating Gforces of between 10 and 1000, more specifically between 40 and 400.Typically, for a 98 cm diameter cage, rotation is at a speed of up to800 rpm in order to achieve this effect. Subsequently, rotation speed isreduced and returned to the speed of the wash cycle so as to allow forremoval of the solid particulate cleaning material.

Optionally, following said bead removal operation, said method mayadditionally comprise a rinsing operation, wherein additional water maybe added to said rotatably mounted cylindrical cage in order to effectcomplete removal of any additional cleaning agent employed in thecleaning operation. Water may be added to said cylindrical cage via saidaddition port mounted on said access door. Again, addition mayoptionally be carried out by means of a spray head in order to achievebetter distribution of the rinsing water in the washload. Alternatively,said addition may be via the separating means, or by overfilling thesecond, lower chamber of said apparatus with water such that it entersthe first, upper chamber and thereby partially submerges said rotatablymounted cylindrical cage and enters into said cage. Following rotationat the same speed as during the wash cycle, water is removed from saidcage by allowing the water level to fall as appropriate and, whatevermethod of rinse water addition is employed, the speed of rotation of thecage is then increased so as to achieve a measure of drying of thesubstrate. Typically, for a 98 cm diameter cage, rotation is at a speedof up to 800 rpm in order to achieve this effect. Subsequently, rotationspeed is reduced and returned to the speed of the wash cycle, therebyallowing for final removal of any remaining solid particulate cleaningmaterial. Said rinsing and drying cycles may be repeated as often asdesired.

Optionally, said rinse cycle may be used for the purposes of substratetreatment, involving the addition of treatment agents such asanti-redeposition additives, optical brighteners, perfumes, softenersand starch to the rinse water.

Said solid particulate cleaning material is preferably subjected to acleaning operation in said lower chamber by sluicing said chamber withclean water in the presence or absence of a cleaning agent, such as asurfactant. Optionally, this water may be heated. Alternatively,cleaning of the solid particulate cleaning material may be achieved as aseparate stage in said rotatably mounted cylindrical cage, again usingwater which may optionally be heated.

Generally, any remaining solid particulate cleaning material on said atleast one substrate may be easily removed by shaking the at least onesubstrate. If necessary, however, further remaining solid particulatecleaning material may be removed by suction means, preferably comprisinga vacuum wand.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further illustrated by reference to thefollowing drawings, wherein:

FIGS. 1(a) and (b) show an apparatus according to the invention, andillustrate aspects of the recirculation means of the apparatus;

FIG. 2 shows a pattern of stains (i)-(ix) applied to a single piece ofcotton fabric in order to make up a standard stain set.;

FIG. 3 represents cleaning results by stain type.;

FIG. 4 represents cleaning results by average over all stains.;

FIG. 5 represents cleaning of sebum results.; and

FIG. 6 represents redeposition results.

DETAILED DESCRIPTION OF THE INVENTION

The apparatus according to the invention may be used for the cleaning ofany of a wide range of substrates including, for example, plasticsmaterials, leather, paper, cardboard, metal, glass or wood. In practice,however, said apparatus is principally designed for use in the cleaningof substrates comprising textile fibre garments, and has been shown tobe particularly successful in achieving efficient cleaning of textilefibres which may, for example, comprise either natural fibres, such ascotton, or man-made and synthetic textile fibres, for example nylon 6,6,polyester, cellulose acetate, or fibre blends thereof.

Most preferably, the solid particulate cleaning material comprises amultiplicity of polymeric particles. Typically, the polymeric particlescomprise polyalkenes such as polyethylene and polypropylene, polyamides,polyesters or polyurethanes, which may be foamed or unfoamed.Furthermore, said polymers may be linear or crosslinked. Preferably,however, said polymeric particles comprise polyamide or polyesterparticles, most particularly particles of nylon, polyethyleneterephthalate or polybutylene terephthalate, most preferably in the formof beads. Said polyamides and polyesters are found to be particularlyeffective for aqueous stain/soil removal, whilst polyalkenes areespecially useful for the removal of oil-based stains.

Various nylon or polyester homo- or co-polymers may be used including,but not limited to, Nylon 6, Nylon 6,6, polyethylene terephthalate andpolybutylene terephthalate. Preferably, the nylon comprises Nylon 6,6homopolymer having a molecular weight in the region of from 5000 to30000 Daltons, preferably from 10000 to 20000 Daltons, most preferablyfrom 15000 to 16000 Daltons. The polyester will typically have amolecular weight corresponding to an intrinsic viscosity measurement inthe range of from 0.3-1.5 dl/g as measured by a solution technique suchas ASTM D-4603.

Optionally, copolymers of the above polymeric materials may be employedfor the purposes of the invention. Specifically, the properties of thepolymeric materials may be tailored to specific requirements by theinclusion of monomeric units which confer particular properties on thecopolymer. Thus, the copolymers may be adapted to attract particularstaining materials by including monomer units in the polymer chainwhich, inter alia, are ionically charged, or include polar moieties orunsaturated organic groups. Examples of such groups may include, forexample, acid or amino groups, or salts thereof, or pendant alkenylgroups.

The polymeric particles are of such a shape and size as to allow forgood flowability and intimate contact with the textile fibre. A varietyof shapes of particles can be used, such as cylindrical, spherical orcuboid; appropriate cross-sectional shapes can be employed including,for example, annular ring, dog-bone and circular. Most preferably,however, said particles comprise cylindrical or spherical beads.

The particles may have smooth or irregular surface structures and can beof solid or hollow construction. Particles are of such a size as to havean average mass of 1-35 mg, preferably from 10-30 mg, more preferablyfrom 12-25 mg, and with a surface area of 10-120 mm², preferably from15-50 mm², more preferably from 20-40 mm².

In the case of cylindrical beads, the preferred particle diameter is inthe region of from 1.0 to 6.0 mm, more preferably from 1.5 to 4.0 mm,most preferably from 2.0 to 3.0 mm, and the length of the beads ispreferably in the range from 1.0 to 4.0 mm, more preferably from 1.5 to3.5 mm, and is most preferably in the region of 2.0 to 3.0 mm.Typically, for spherical beads, the preferred diameter of the sphere isin the region of from 1.0 to 6.0 mm, more preferably from 2.0 to 4.5 mm,most preferably from 2.5 to 3.5 mm.

In order to provide additional lubrication to the cleaning system andthereby improve the transport properties within the system, water isadded to the system. Thus, more efficient transfer of the at least onecleaning material to the substrate is facilitated, and removal ofsoiling and stains from the substrate occurs more readily. Optionally,the soiled substrate may be moistened by wetting with mains or tap waterprior to loading into the apparatus of the invention. In any event,water is added to the rotatably mounted cylindrical cage of theapparatus according to the invention such that the washing treatment iscarried out so as to achieve a water to substrate ratio which ispreferably between 2.5:1 and 0.1:1 w/w; more preferably, the ratio isbetween 2.0:1 and 0.8:1, with particularly favourable results havingbeen achieved at ratios such as 1.75:1, 1.5:1, 1.2:1 and 1.1:1. Mostconveniently, the required amount of water is introduced into therotatably mounted cylindrical cage of the apparatus according to theinvention after loading of the soiled substrate into said cage. Anadditional amount of water will migrate into the cage during thecirculation of the solid particulate cleaning material, but the amountof carry over is minimised by the action of the separating means.

Whilst, in one embodiment, the method of the invention envisages thecleaning of a soiled substrate by the treatment of a moistened substratewith a formulation which essentially consists only of a multiplicity ofpolymeric particles, in the absence of any further additives, optionallyin other embodiments the formulation employed may additionally compriseat least one cleaning agent. Said at least one cleaning agent mayinclude at least one cleaning material. Preferably, the at least onecleaning material comprises at least one detergent composition.Optionally, said at least one cleaning material is mixed with saidpolymeric particles but, in a preferred embodiment, each of saidpolymeric particles is coated with said at least one cleaning material.

The principal components of the detergent composition comprise cleaningcomponents and post-treatment components. Typically, the cleaningcomponents comprise surfactants, enzymes and bleach, whilst thepost-treatment components include, for example, anti-redepositionadditives, perfumes and optical brighteners.

However, the detergent formulation may optionally include one or moreother additives such as, for example builders, chelating agents, dyetransfer inhibiting agents, dispersants, enzyme stabilizers, catalyticmaterials, bleach activators, polymeric dispersing agents, clay soilremoval agents, suds suppressors, dyes, structure elasticizing agents,fabric softeners, starches, carriers, hydrotropes, processing aidsand/or pigments.

Examples of suitable surfactants may be selected from non-ionic and/oranionic and/or cationic surfactants and/or ampholytic and/orzwitterionic and/or semi-polar nonionic surfactants. The surfactant istypically present at a level of from about 0.1%, from about 1%, or evenfrom about 5% by weight of the cleaning compositions to about 99.9%, toabout 80%, to about 35%, or even to about 30% by weight of the cleaningcompositions.

The compositions may include one or more detergent enzymes which providecleaning performance and/or fabric care benefits. Examples of suitableenzymes include, but are not limited to, hemicellulases, peroxidases,proteases, other cellulases, other xylanases, lipases, phospholipases,esterases, cutinases, pectinases, keratanases, reductases, oxidases,phenoloxidases, lipoxygenases, ligninases, pullulanases, tannases,pentosanases, malanases, [beta]-glucanases, arabinosidases,hyaluronidase, chondroitinase, laccase, and amylases, or mixturesthereof. A typical combination may comprise a mixture of enzymes such asprotease, lipase, cutinase and/or cellulase in conjunction with amylase.

Optionally, enzyme stabilisers may also be included amongst the cleaningcomponents. In this regard, enzymes for use in detergents may bestabilised by various techniques, for example by the incorporation ofwater-soluble sources of calcium and/or magnesium ions in thecompositions.

The compositions may include one or more bleach compounds and associatedactivators. Examples of such bleach compounds include, but are notlimited to, peroxygen compounds, including hydrogen peroxide, inorganicperoxy salts, such as perborate, percarbonate, perphosphate,persilicate, and mono persulphate salts (e.g. sodium perboratetetrahydrate and sodium percarbonate), and organic peroxy acids such asperacetic acid, monoperoxyphthalic acid, diperoxydodecanedioic acid,N,N′-terephthaloyl-di (6-aminoperoxycaproic acid),N,N′-phthaloylaminoperoxycaproic acid and amidoperoxyacid. Bleachactivators include, but are not limited to, carboxylic acid esters suchas tetraacetylethylenediamine and sodium nonanoyloxybenzene sulphonate.

Suitable builders may be included in the formulations and these include,but are not limited to, the alkali metal, ammonium and alkanolammoniumsalts of polyphosphates, alkali metal silicates, alkaline earth andalkali metal carbonates, aluminosilicates, polycarboxylate compounds,ether hydroxypolycarboxylates, copolymers of maleic anhydride withethylene or vinyl methyl ether,1,3,5-trihydroxybenzene-2,4,6-trisulphonic acid, andcarboxymethyl-oxysuccinic acid, various alkali metal, ammonium andsubstituted ammonium salts of polyacetic acids such as ethylenediaminetetraacetic acid and nitrilotriacetic acid, as well as polycarboxylatessuch as mellitic acid, succinic acid, oxydisuccinic acid, polymaleicacid, benzene 1,3,5-tricarboxylic acid, carboxymethyloxysuccinic acid,and soluble salts thereof.

The compositions may also optionally contain one or more copper, ironand/or manganese chelating agents and/or one or more dye transferinhibiting agents.

Suitable polymeric dye transfer inhibiting agents include, but are notlimited to, polyvinylpyrrolidone polymers, polyamine N-oxide polymers,copolymers of N-vinylpyrrolidone and N-vinylimidazole,polyvinyloxazolidones and polyvinylimidazoles or mixtures thereof.

Optionally, the detergent formulations can also contain dispersants.Suitable water-soluble organic materials are the homo- or co-polymericacids or their salts, in which the polycarboxylic acid may comprise atleast two carboxyl radicals separated from each other by not more thantwo carbon atoms.

Said anti-redeposition additives are physico-chemical in their actionand include, for example, materials such as polyethylene glycol,polyacrylates and carboxy methyl cellulose.

Optionally, the compositions may also contain perfumes Suitable perfumesare generally multi-component organic chemical formulations which cancontain alcohols, ketones, aldehydes, esters, ethers and nitrilealkenes, and mixtures thereof. Commercially available compounds offeringsufficient substantivity to provide residual fragrance includeGalaxolide(1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran),Lyral (3- and 4-(4-hydroxy-4-methyl-pentyl) cyclohexene-1-carboxaldehydeand Ambroxan((3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyl-2,4,5,5a,7,8,9,9b-octahydro-1H-benzo[e][1]benzofuran). One example of a commercially available fully formulatedperfume is Amour Japonais supplied by Symrise® AG.

Suitable optical brighteners fall into several organic chemical classes,of which the most popular are stilbene derivatives, whilst othersuitable classes include benzoxazoles, benzimidazoles,1,3-diphenyl-2-pyrazolines, coumarins, 1,3,5-triazin-2-yls andnaphthalimides. Examples of such compounds include, but are not limitedto,4,4′-bis[[6-anilino-4(methylamino)-1,3,5-triazin-2-yl]amino]stilbene-2,2′-disulphonicacid,4,4′-bis[[6-anilino-4-[(2-hydroxyethyhmethylamino]-1,3,5-triazin-2-yl]amino]stilbene-2,2′-disulphonicacid, disodium salt,4,4′-Bis[[2-anilino-4-[bis(2-hydroxyethy)amino]-1,3,5-triazin-6-yl]amino]stilbene-2,2′-disulphonicacid, disodium salt,4,4′-bis[(4,6-dianilino-1,3,5-triazin-2-yhamino]stilbene-2,2′-disulphonicacid, disodium salt, 7-diethylamino-4-methylcoumarin,4,4′-Bis[(2-anilino-4-morpholino-1,3,5-triazin-6-yl)amino]-2,2′-stilbenedisulphonicacid, disodium salt, and 2,5-bis(benzoxazol-2-yl)thiophene.

Said agents may be used either alone or in any desired combination andmay be added to the cleaning system at appropriate stages during thecleaning cycle in order to maximise their effects.

In any event, however, when the method of the invention is performed inthe presence of at least one additional cleaning agent, the quantity ofsaid cleaning agent required in order to achieve satisfactory cleaningperformance is significantly reduced from the quantities required withthe methods of the prior art. This, in turn, has beneficial effects interms of the reduced quantity of rinse water that is subsequentlyrequired to be used.

The ratio of solid particulate cleaning material to substrate isgenerally in the range of from 0.1:1 to 10:1 w/w, preferably in theregion of from 0.5:1 to 5:1 w/w, with particularly favourable resultsbeing achieved with a ratio of between 1:1 and 3:1 w/w, and especiallyat around 2:1 w/w. Thus, for example, for the cleaning of 5 g of fabric,10 g of polymeric particles, optionally coated with surfactant, would beemployed in one embodiment of the invention. The ratio of solidparticulate cleaning material to substrate is maintained at asubstantially constant level throughout the wash cycle.

The apparatus and the method of the present invention may be used foreither small or large scale batchwise processes and find application inboth domestic and industrial cleaning processes.

As previously noted, the method of the invention finds particularapplication in the cleaning of textile fibres. The conditions employedin such a cleaning system do, however, allow the use of significantlyreduced temperatures from those which typically apply to theconventional wet cleaning of textile fabrics and, as a consequence,offer significant environmental and economic benefits. Thus, typicalprocedures and conditions for the wash cycle require that fabrics aregenerally treated according to the method of the invention at, forexample, temperatures of between 5 and 95° C. for a duration of between5 and 120 minutes in a substantially sealed system. Thereafter,additional time is required for the completion of the rinsing and beadseparation stages of the overall process, so that the total duration ofthe entire cycle is typically in the region of 1 hour. The preferredoperating temperatures for the method of the invention are in the rangeof from 10 to 60° C. and, more preferably, from 15 to 40° C.

The cycle for removal of solid particulate material may optionally beperformed at room temperature and it has been established that optimumresults are achieved at cycle times of between 2 and 30 minutes,preferably between 5 and 20 minutes.

The results obtained are very much in line with those observed whencarrying out conventional wet (or dry) cleaning procedures with textilefabrics. The extent of cleaning and stain removal achieved with fabricstreated by the method of the invention is seen to be very good, withparticularly outstanding results being achieved in respect ofhydrophobic stains and aqueous stains and soiling, which are oftendifficult to remove. The energy requirement, the total volume of waterused, and the detergent consumption of the method of the invention areall significantly lower than those levels associated with the use ofconventional aqueous washing procedures, again offering significantadvantages in terms of cost and environmental benefits.

Additionally, it has been demonstrated that re-utilisation of thepolymer particles is possible, allowing for the performance of multiplewashes with the same solid particulate cleaning material. Re-use of theparticles in this way for repeat cleaning procedures providessignificant economic benefits and the achievement of satisfactoryresults after multiple washes is assisted by the nature of the process,which relies on continuous cleaning of the particulate cleaning materialas an integral part of the procedure, although it generally found thatsome deterioration in performance is eventually observed. In a typicalexample of an operating cycle according to the method of the invention,an initial addition of solid particulate cleaning material(approximately 43 kg) is added to a washload of soiled substrate (15 kg)in the rotatably mounted cylindrical cage of 98 cm diameter, after whichrotation of the cage commences at around 40 rpm. Thereafter, furthersolid particulate cleaning material (10 kg) is pumped into saidrotatably mounted cylindrical cage via the separating means and controlmeans approximately every 30 seconds throughout the duration of the washcycle which may typically continue for around 30 minutes. The system isthereby designed to pump and add solid particulate cleaning material ata sufficient rate to maintain roughly the same level of solidparticulate cleaning material in the rotatably mounted cylindrical cage(approximately 2.9:1 by weight, for 43 kg of beads and 15 kg of cloth)throughout the wash.

Thus, during the wash cycle, the solid particulate cleaning material iscontinually falling out of the rotatably mounted cylindrical cagethrough its perforations, and is being recycled and added, together withfresh cleaning material, via the separating means and control means.This process may either be controlled manually, or operatedautomatically. The rate of exit of the solid particulate cleaningmaterial from the rotatably mounted cylindrical cage is essentiallycontrolled by means of its specific design. The key parameters in thisregard include the size of the perforations, the number of perforationsand the pattern of the perforations.

Generally, the perforations are sized at around 2-3 times the averageparticle diameter of the solid particulate cleaning material which, in atypical example, results in perforations having a diameter of no greaterthan 10.0 mm.

In a preferred embodiment of the invention, a rotatably mountedcylindrical cage (diameter 98 cm, depth 65 cm) would be drilled to havestripes of 8.0 mm diameter perforations running from front to back inapproximately 9 cm wide strips alternating with solid sections, so thatonly around 34% of the surface area of the cylindrical walls of the cagecomprises perforations. The perforations are preferably banded instripes on the cylindrical walls of the rotatably mounted cylindricalcage or, alternatively, uniformly distributed over the cage wall, ratherthan being exclusively located, for example, in one half of the cage.

The rate of exit of the solid particulate cleaning material from therotatably mounted cylindrical cage is also affected by the speed ofrotation of said cage, with higher rotation speeds increasing thecentripetal force so as to increase the tendency to push the solidparticulate cleaning material out of the perforations. However, highercage rpm values also compress the substrate being cleaned, so as to trapthe cleaning material within folds thereof. The most suitable rotationspeeds are, therefore, generally found to be between 30 and 40 rpm at 98cm cage diameter, or those which generate G values of between 0.49 and0.88. The maximum rotation speed in order to avoid bead trapping ingarments is found to be around 42 rpm (G=0.97).

In addition, the moisture level in the wash also has an effect, withwetter substrates tending to retain cleaning material for a longer timethan drier substrates. Consequently, overwetting of substrate can, ifnecessary, be employed in order to further control the rate of exit ofsolid particulate cleaning material.

On completion of the wash cycle, addition of solid particulate cleaningmaterial to the rotatably mounted cylindrical cage is ceased, and thecage is rotated for a short time (about 2 minutes) at low rpm (30-40rpm; G=0.49-0.88) to allow the bulk of the solid particulate cleaningmaterial to leave the cage. The cage is then rotated at high speed(between 300 and 800 rpm; G=49.3-350.6) for about 2 minutes in order toextract some liquid and dry the substrate to an extent. The rotationspeed is then returned to the same low rpm as in the wash cycle in orderto complete the removal of cleaning material; this generally takesaround 20 minutes.

The method of the invention has been shown to be particularly successfulin the removal of cleaning material from the cleaned substrate afterwashing, and tests with cylindrical polyester beads, and nylon beadscomprising Nylon 6,6 polymer, have indicated bead removal efficacy suchthat on average <20 beads per garment remain in the washload at the endof the bead separation cycle. Generally, this can be further reduced toan average of <10 beads per garment and, in optimised cases wherein a 20minute separation cycle is employed, an average of <5 beads per garmentis typically achieved. Following said bead removal operation a series ofrinses is carried out, wherein additional water is sprayed into therotatably mounted cylindrical cage in order to effect complete removalof any additional cleaning agent employed in the cleaning operation. Inthis embodiment of the invention, a spray head is used, which is mountedin an addition port on the access door. The use of said spray head hasbeen shown to better distribute the rinsing water in the washload. Bythis means the overall water consumption during the rinsing operationcan also be minimised (3:1 rinse water:cloth, typically, per rinse). Thecage is rotated at low speeds again during rinse water addition (30-40rpm, G=0.49-0.88 for 98 cm diameter cage), but after this operation hasceased the cage speed is once again increased to achieve a measure ofdrying of the substrate (300-800 rpm, G=49.3-350.6). Subsequently,rotation speed is reduced and returned to the speed of the wash cycle soas to allow for final removal of any remaining solid particulatecleaning material. Said rinsing and drying cycles may be repeated asoften as desired (3 times is typical).

Referring to the figures provided herewith, there is seen in FIGS. 1(a)and (b) an apparatus according to the invention comprising housing means(1) having a first upper chamber (11 having mounted therein a rotatablymounted cylindrical cage in the form of drum (2) with perforations (14),as one example, shown within drum (2) and a second lower chambercomprising sump (3) located beneath said cylindrical cage. The apparatusadditionally comprises, as first recirculation means, bead and waterriser pipe (4) which feeds into a bead separation vessel (5), includingfilter material, typically in the form of a wire mesh, and a beadrelease gate valve which feeds into bead delivery tube (6) mounted incage entry (7). The first recirculation means is driven by bead pump(8). Additional recirculation means comprises return water pipe (9),which allows water to return from the bead separation vessel (5) to thesump (3) under the influence of gravity. The apparatus also comprisesaccess means shown as loading door (10), though which material forcleaning may be loaded into drum (2). A delivery means (12) is shown, asan example, for delivery of water and optionally cleaning agents intothe apparatus. Additional pumping means (13) are typically locatedwithin sump (3) to promote circulation and mixing of the contents.

Thus, FIG. 1(a) illustrates a section of the first recirculation system,wherein the solid particulate cleaning material in the form of beadspasses from the bead separation vessel (5) through the bead deliverytube (6) and into the drum (2), and FIG. 1(b) shows other sections ofthe first recirculation system, wherein the solid particulate cleaningmaterial comprising beads and water is driven by bead pump (8) from theheated sump (3) through the bead and water riser pipe (4) to the beadseparation vessel (5), from which separated water returns to the sumpvia return water pipe (9) under the influence of gravity. The main motor(20) of the apparatus, responsible for driving the drum (2), is alsodepicted.

In operation, the sump (3), together with its contents (water andpolymer beads) may be heated by heater pads attached to the outersurface of the sump (3). The bead pump (8) pumps the beads and water upthrough the riser pipe (4) to the bead separation vessel (5) where thebeads are retained within the vessel (5) whilst the drained waterreturns to the sump via a return pipe (9). The rigid filter materialwithin the separation vessel allows the water carried with the beads toescape from within the mass of the beads, whilst the gate valve retainsthe beads within the vessel (5). Further beads may then be pumped intothe separation vessel (5). The water drains from the vessel (5) andreturns to the sump (3). When the valve in vessel (5) is opened, thebeads pass through the valve and travel down the bead delivery tube (6),through the cage entry (7) and in to the drum (2). Cold water may beadded to the contents of the drum (2) via a cold water feed port locatedin cage entry (7). The wash load is placed into the drum (2) throughopenable loading door (10), and detergent is added to the system via aport in the sump (3). The system temperature is monitored via atemperature probe, preferably mounted in bead delivery tube (6), whilsta water pump circulates water around the sump (3).

Hence, the system provides a means of adding polymer beads to a washload, performing the washing cycle, and then separating the beads fromthe wash load once the washing cycle is complete. The washing processmay be conveniently illustrated by describing one complete wash cycle.

Thus, polymer beads together with the required addition of water toachieve efficient pumping are optionally heated to operating temperaturein the sump (3) by the sump heater pads, and the water is recirculatedthrough the beads using the water pump to ensure that a uniform bulktemperature is achieved. Once the required operating temperature isachieved, the wash load is placed into the drum (2) and the loading door(10) is closed. Initially, cold water is added to the wash load via thecold water feed port to ensure that any stains (such as egg) are not‘baked’ on to the fabric when the warm wash water and beads areintroduced. Cleaning materials such as detergents may be added to thepolymer beads in the sump, but are preferably added at this stage, withwater; said addition may be made either via an addition port (not shown)mounted on the door (10) or through the bead separation vessel (5) andbead delivery tube (6). The wash load is agitated gently to disperse thecold water evenly amongst the load and fully wet out the cloth.Additional cleaning materials, of which bleach is a typical example, maybe added with more, optionally heated, water at later stages during thewash cycle via the same means of addition.

Once the initial working temperature has been reached by the beads andwater within the sump, the bead pump (8) pumps a mixture of beads andwater up to the bead separation vessel (5). Excess water is allowed todrain back to the sump (3) and the valve is then opened to release thebeads into the drum (2) via the bead delivery tube (6). This operationis repeated a number of times until the required quantity of beads hasbeen delivered to the drum (2).

The system then performs a wash cycle in a similar manner to a standardwashing machine with the cage rotating at between 30 and 40 rpm(G=0.49-0.88 for a 98 cm cylindrical cage) for several revolutions inone direction, then rotating a similar number of rotations in theopposite direction. This sequence is repeated for up to 60 minutes.During this time, the beads are continually falling though the cageperforations into the sump (3) and being pumped back by the bead pump(8) to the bead separation vessel (5) from which, together with freshbeads as necessary, they are re-introduced into the drum (2).

On completion of the wash cycle, introduction of beads into drum (2)ceases whilst the beads remain free to fall through the cageperforations and out into the sump (3). Following a short high speedrotation to remove some liquor from the drum and partially dry out thecleaned substrate, a series of slow speed rotations and counterrotations is performed to encourage the beads to fall through theperforations in the drum (2) and return to the sump (3). This process iscontinued until virtually all of the beads have been removed from withinthe drum (2). At any point during this bead separation sequence, air canbe blown into the drum to disrupt and cause the billowing of the clothto aid bead removal. The wash load can then be removed from the drum (2)via the loading door (10).

In a preferred bead removal sequence, the drum (2) is initially rotatedfor 2 minutes at between 300 and 800 rpm (G=49.3-350.6 for a 98 cmdiameter drum), then for 20 minutes at between 30 and 40 rpm, duringwhich time the direction of rotation is reversed approximately every 30seconds in order to re-orientate the substrate and allow the beads tofall from the substrate, thereby effecting efficient bead removal. In aseparate optional step, the wash load may be rinsed with water followingthe wash cycle. In further optional stages, following their removal fromthe drum and transfer to the sump, the beads may be cleaned by sluicingthe sump with clean water in the presence or absence of a cleaningagent, such as a surfactant. Alternatively, cleaning of the beads may becarried out by washing them alone in the drum following removal of thewash load.

The invention will now be further illustrated, though without in any waylimiting the scope thereof, by reference to the following examples andassociated illustrations.

EXAMPLE

Example 1

Woven cotton fabric (194 gm⁻², Whaleys, Bradford, U.K.) was stained withcoffee, lipstick, ball point pen, tomato ketchup, boot polish, grass,vacuum dirt, curry sauce and red wine following the methods describedbelow:

(i) Coffee

10 g of Morrisons® Full Roast coffee powder was dissolved in 50 mldistilled water at 70° C. A 1 cm³ aliquot of the ensuing solution wasapplied to the fabric using a synthetic sponge, within the confines of a5 cm diameter circular plastic template; the stained fabric was thenallowed to dry at ambient temperature (23° C.), after which the fabricwas aged prior to use, by storage in the dark for 4 days.

(ii) Lipstick

Revlon® Super Lustrous lipstick (copper frost shade) was applied to thefabric using a synthetic sponge to provide a uniform coverage within theconfines of a 5 cm diameter circular plastic template. The fabric wasthen aged following the procedure recounted for coffee.

(iii) Ball Point Pen

A black Paper Mate® Flex Grip Ultra ball point pen was used to uniformlycover the fabric within the confines of a 5 cm diameter circular plastictemplate. The fabric was then aged following the procedure recounted forcoffee.

(iv) Tomato Ketchup

Heinz® tomato ketchup was applied to the fabric using a synthetic spongeto provide a uniform coverage within the confines of a 5 cm diametercircular plastic template. The fabric was then aged following theprocedure recounted for coffee.

(v) Boot Polish

Kiwi® black boot polish was applied to the fabric using a syntheticsponge to provide a uniform coverage within the confines of a 5 cmdiameter circular plastic template. The fabric was then aged followingthe procedure recounted for coffee.

(vi) Grass

Grass was collected manually from an MG7 (National VegetationClassification) source. 10 g of the grass was chopped with scissors andblended with 200 ml of tap water using an electronic blender. Themixture was then filtered using a metal sieve, and the filtrate used asthe staining medium. This was applied to the fabric using a syntheticsponge to provide a uniform coverage within the confines of a 5 cmdiameter circular plastic template. The fabric was then aged followingthe procedure recounted for coffee.

(vii) Vacuum Dirt

Vacuum dirt was collected manually from a general domestic vacuum bag.25 g of vacuum dirt was mixed with 100 ml of tap water, and the mixtureused to stain the fabric. This was applied to the fabric using asynthetic sponge to provide a uniform coverage within the confines of a5 cm diameter circular plastic template. The fabric was then agedfollowing the procedure recounted for coffee.

(viii) Curry Sauce

Morrisons® own brand curry sauce was applied directly to the fabricusing a synthetic sponge to provide a uniform coverage within theconfines of a 5 cm diameter circular plastic template. The fabric wasthen aged following the procedure recounted for coffee.

(ix) Red Wine

“Spanish Red Wine” purchased at Morrisons® was applied directly to thefabric using a synthetic sponge to provide a uniform coverage within theconfines of a 5 cm diameter circular plastic template. The fabric wasthen aged following the procedure recounted for coffee.

Each of the stains (i)-(ix) was applied to a single (36 cm×30 cm) pieceof cotton fabric in the pattern shown in FIG. 2, in order to make up astandard stain set.

Cleaning trials were then carried out using a set of trial and controlconditions, as set out in Table 1. The trials involved the use of apreferred apparatus as hereinbefore defined according to the method ofthe invention (“Xeros—Gen 1” XP1), whilst control cleaning trials werecarried out using a standard domestic washing machine (BEKO® WM5120W,XP2 and XP3). In both cases (XP1, XP2 and XP3) the standard stain setswere added at 1/kg of washload, and a simulated sebum grease stain of 10g/kg of washload was also incorporated as impregnated cotton cloth (WFKSBL2004). This cloth is used to better simulate the domestic washingenvironment where such collar and cuff grease is the dominant stain(making up some 80% of the overall stain loading). Sebum is derived fromthe skin's sebaceous glands. The XP1 process was undertaken at ambienttemperature (measured as 15° C.) with a 24 kg cotton andpolyester/cotton mixed fabric washload, 28.8 litres of wash water (i.e.1.2 litres/kg washload) and 65 kg of INVISTATM 1101 polyester beads(i.e. 2.7 kg/kg washload). A rinse cycle of four 18 litre rinses wasemployed (spin speed 300 rpm in a 98 cm diameter drum; G=49.3). Thetotal water consumption (including wash and rinse) was, therefore, only100.8 litres, or 4.2 litres/kg washload. The detergent used was UnileverPersil Small & Mighty® biological liquid at 3.7 g/kg of washload. Thetotal cycle time was 95 minutes.

The domestic controls (XP2 and XP3) were carried out with a 4 kgwashload, even though the BEKO® WM5120W is rated as a 5 kg machine. Thisis the widely accepted average washload size for the European domesticmarket and it, in turn, makes this control more rigorous. The increasedullage in the drum results in more mechanical action and a better washperformance. It should also be noted that whilst XP2 was run at ambientwash temperature (measured as 15° C.), XP3 was run at a higher washtemperature (40° C.). In addition, both the XP2 and XP3 were run with a9.3 g/kg washload of detergent, which was considerably more than forXP1, and the water consumption was also higher (wash plus rinse 56 kg,or 14.0 litres/kg of washload). Finally, the total process cycle timefor XP2 and XP3 was 127 minutes, which is considerably longer than forXP1, using the process according to the invention. These parameters werea function of the cycle chosen on the BEKO® machine (40° C., cotton),and they also obviously increased the rigour of the control. It shouldbe noted that the BEKO® WM5120W does not have an ambient cycle in itsstandard programme choices; hence, the ambient cycle was achieved inthis instance by disconnecting the heater from the machine andre-running the 40° C. cotton cycle, so that XP3 had the same cycle timeas XP2.

The test parameters are summarised in Table 1.

TABLE 1 XP1, XP2 & XP3 Wash Test Details Detergent Detergent Water WashCycle Machine Washload Dosage Dosage Consumption Temperature Time Test #Type (kg) (g) (g/kg) (litres/kg) (° C.) (mins) XP1 Xeros - 24 89 3.7 4.215 95 (Trial) Gen1 XP2 BEKO ® 4 37 9.3 14.0 15 127 (Control) WM5120W XP3BEKO ® 4 37 9.3 14.0 40 127 (Control) WM5120W

The level of cleaning achieved was assessed using colour measurement.Reflectance values of samples were measured using a DatacolorSpectraflash SF600 spectrophotometer interfaced to a personal computer,employing a 10° standard observer, under illuminant D₆₅,with the UVcomponent included and specular component excluded; a 3 cm viewingaperture was used. Measurements using a single thickness of fabric weremade. The CIE L* colour co-ordinate was taken for each stain and thenthe average values were recorded as ‘Enzyme’ (grass and tomato ketchupstain average), ‘Oxidise’ (coffee, red wine and ball point pen average),and ‘Particulate’ (vacuum dirt, boot polish and lipstick stain average),with the curry sauce stain being measured individually. The sebum stainremoval and level of redeposition on the cloth (i.e. the backgroundwhiteness on each stain set) were also measured individually.

These results are set out in FIGS. 3 to 6, with higher values indicatingbetter cleaning performance, or redeposition control. Comparison of XP1with XP2 shows the cleaning carried out in the apparatus of theinvention gave superior results for each stain class (FIG. 3), and whenaveraged over all stains (FIG. 4)—even with the reduced detergent andwater levels used in XP1 versus XP2, and despite the longer cycle timeof XP2. Sebum removal was significantly better with the method of theinvention (FIG. 5), whilst redeposition was similar (FIG. 6).

Comparison of XP1 and XP3 shows the cleaning carried out in theapparatus of the invention gave comparable performance for each stainclass (FIG. 3—slightly better with particulate), and when averaged overall stains (FIG. 4)—now even despite the reduced detergent and waterlevels and significantly lower wash temperature used in XP1 versus XP3,and the longer cycle time of XP3. Sebum removal and redeposition wereboth similar (FIGS. 5 and 6 respectively).

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of them mean “including but notlimited to”, and they are not intended to (and do not) exclude othermoieties, additives, components, integers or steps. Throughout thedescription and claims of this specification, the singular encompassesthe plural unless the context otherwise requires. In particular, wherethe indefinite article is used, the specification is to be understood ascontemplating plurality as well as singularity, unless the contextrequires otherwise.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

1. An apparatus for use in the cleaning of soiled substrates, saidapparatus comprising: (a) housing means, having: (i) a first upperchamber having mounted therein a rotatably mounted cylindrical cage, and(ii) a second lower chamber located beneath said cylindrical cage, whichfunctions as a collection chamber for cleaning media comprising a solidparticulate cleaning material; (b) at least one recirculation meansfacilitating recirculation of said solid particulate cleaning materialfrom said second lower chamber to said rotatably mounted cylindricalcage for re-use in cleaning operations; (c) access means allowing accessto the inside of the cylindrical cage for loading at least one soiledsubstrate into said cylindrical cage, wherein said access means isclosable so as to provide a sealed system; (d) pumping means comprisedin a first recirculation means of the at least one recirculation means;and (e) a multiplicity of delivery means for delivery of water andoptionally cleaning agents into the apparatus, wherein said rotatablymounted cylindrical cage comprises a drum comprising perforated sidewalls, wherein up to 60% of the surface area of said cylindrical sidewalls comprises perforations, and said perforations comprise holeshaving a diameter of no greater than 25.0 mm and wherein said apparatusis for use in the cleaning of the soiled substrates using a formulationcomprising a solid particulate cleaning material and wash water.
 2. Anapparatus as claimed in claim 1 wherein said rotatably mountedcylindrical cage has a capacity of 10 to 7000 litres and optionallycomprises a cylinder with a diameter of 75 to 120 cm and a length ofbetween 40 and 100 cm.
 3. An apparatus as claimed in claim 1 whereinrotation of said rotatably mounted cylindrical cage is effected by useof drive means, wherein said drive means optionally comprises electricaldrive means and said electrical drive means optionally comprises anelectric motor.
 4. An apparatus as claimed in claim 1 wherein saidsecond lower chamber functions as a collection chamber for said solidparticulate cleaning material and comprises a sump.
 5. An apparatus asclaimed in claim 1 wherein said at least one recirculation meansfacilitates recirculation of said solid particulate cleaning materialfrom said second lower chamber to said rotatably mounted cylindricalcage, for re-use in cleaning operations and comprises ducting connectingsaid second chamber and said rotatably mounted cylindrical cage, whereinsaid ducting comprises separating means for separating said solidparticulate cleaning material from water, wherein said separating meansoptionally comprises a vessel located above said cylindrical cage.
 6. Anapparatus as claimed in claim 1 which includes a second recirculationmeans, wherein said second recirculation means allows for the return ofwater separated by a separating means to said second lower chamber. 7.An apparatus as claimed in claim 1 wherein said second lower chambercomprises additional pumping means to promote circulation and mixing ofthe contents of the second lower chamber.
 8. A method for cleaning asoiled substrate, said method comprising the treatment of the substratewith a formulation comprising solid particulate cleaning material andwash water, wherein said method is carried out in an apparatus accordingto claim
 1. 9. A method for cleaning a soiled substrate, said methodcomprising the steps of: (a) introducing a solid particulate cleaningmaterial and water into the second lower chamber of an apparatus asclaimed in claim 1; (b) agitating and heating said solid particulatecleaning material and water; (c) loading at least one soiled substrateinto said rotatably mounted cylindrical cage via access means; (d)closing the access means so as to provide a substantially sealed system;(e) introducing said solid particulate cleaning material and water intosaid rotatably mounted cylindrical cage via recirculating means; (f)operating the apparatus for a wash cycle, wherein said rotatably mountedcylindrical cage is caused to rotate and wherein fluids and solidparticulate cleaning material are caused to fall through perforations insaid rotatably mounted cylindrical cage into said second lower chamberin a controlled manner; (g) operating pumping means so as to transferfresh solid particulate cleaning material and recycle used solidparticulate cleaning material to separating means; (h) operating controlmeans so as to add said fresh and recycled solid particulate cleaningmaterial to said rotatably mounted cylindrical cage in a controlledmanner; and (i) continuing with steps (ft, (g) and (h) as required toeffect cleaning of the soiled substrate.
 10. A method as claimed inclaim 8 which additionally comprises a rinsing operation whereinadditional water is added to said rotatably mounted cylindrical cage.11. A method as claimed in claim 10 wherein substrate treatment agentsare added to the rinse water during said rinsing operation, wherein saidsubstrate treatment agents are optionally selected fromanti-redeposition additives, optical brighteners, perfumes, softenersand starch.
 12. A method as claimed in claim 8 wherein at least oneadditional cleaning agent is added to said apparatus, wherein said atleast one additional cleaning agent is optionally either added to thelower chamber of said apparatus with said solid particulate cleaningmaterial, heated to the desired temperature therein, and the introduced,via said first recirculation means, into said cylindrical cage, or ispre-mixed with water and added to said cylindrical cage via an additionport mounted on said access means, and wherein said at least oneadditional cleaning agent optionally comprises at least one detergentcomposition which optionally comprises cleaning components andpost-treatment components, wherein said cleaning components optionallycomprise surfactants, enzymes and bleach and said post-treatmentcomponents optionally comprise anti-redeposition additives, perfumes andoptical brighteners, and which optionally additionally comprises atleast one other additive selected from builders, chelating agents, dyetransfer inhibiting agents, dispersants, enzyme stabilizers, catalyticmaterials, bleach activators, polymeric dispersing agents, clay soilremoval agents, suds suppressors, dyes, structure elasticizing agents,fabric softeners, starches, carriers, hydrotropes, processing aids andpigments.
 13. A method as claimed in claim 8 wherein, during the washcycle, rotation of said rotatably mounted cylindrical cage is caused tooccur at a G force of less than 1 and wherein, on completion of the washcycle, feeding of solid particulate cleaning material into saidrotatably mounted cylindrical cage ceases and the G force on the cage isincreased in order to effect a measure of drying of the cleanedsubstrate, wherein said increased G force is optionally between 10 and1000, and wherein the G force is subsequently reduced to below 1 so asto allow for removal of the solid particulate cleaning material.
 14. Amethod as claimed in claim 8 which additionally comprises separation andrecovery of said solid particulate cleaning material and its re-use insubsequent washes, wherein said solid particulate cleaning material isoptionally subjected to a cleaning operation either (a) in said lowerchamber by sluicing said chamber with clean water or (b) in saidrotatably mounted cylindrical cage.
 15. A method as claimed in claim 8wherein said solid particulate cleaning material comprises amultiplicity of polymeric particles and said polymeric particlesoptionally comprise particles of polyamides, polyesters, polyalkenes orpolyurethanes or their copolymers and said washing treatment isoptionally carried out so as to achieve a water to substrate ratio ofbetween 2.5:1 to 0.1:1 w/w wherein the ratio of solid particulatecleaning material to substrate is optionally in the range of from 0.1:1to 10:1 w/w, and wherein the wash cycle is optionally performed attemperatures of between 5 and 95° C. and for a duration of between 5 and120 minutes.